On the collision rate of small particles in isotropic turbulence Part 2. Finite inertia case

Yong Zhou, Anthony S. Wexler, Lian Ping Wang

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations

Abstract

Numerical experiments have been performed to study the geometric collision rate of heavy particles with finite inertia. The turbulent flow was generated by integrating numerically the full Navier-Stokes equations directly. We found that the collision kernel reached a peak at a particle response time larger than the Kolmogorov time but less than the large-eddy turnover timeΓimplying that both the large-scale and small-scale fluid motion can contributeΓalthough in very different mannersΓto the collision rate. Both numerical results and a stochastic theory show that the collision kernel approaches very slowly to the kinetic theory of Abrahamson (1975) at large τp/TeΓwhere τp is the particle response time and Te is the flow integral time scale. A rapid increase of the collision kernel with the particle response time was observed for small τpkΓwhere τk is the flow Kolmogorov time scale. A small inertia of τpk = 0.5 can lead to an order of magnitude increase in the collision kernel relative to the zero-inertia particles. A scaling law for the collision kernel at small τpk was proposed and confirmed numerically by varying the particle sizeΓinertial response timeΓand flow Reynolds number. A leading-order theory for small τpk was developedΓshowing that the enhanced collision is mainly a result of the nonuniform particle concentration due to the interaction of heavy particles with local flow microstructures.

Original languageEnglish (US)
Title of host publicationAmerican Society of Mechanical Engineers, Fluids Engineering Division (Publication) FED
Place of PublicationNew York, NY, United States
PublisherASME
Volume17
StatePublished - 1997
Externally publishedYes
EventProceedings of the 1997 ASME Fluids Engineering Division Summer Meeting, FEDSM'97. Part 24 (of 24) - Vancouver, Can
Duration: Jun 22 1997Jun 26 1997

Other

OtherProceedings of the 1997 ASME Fluids Engineering Division Summer Meeting, FEDSM'97. Part 24 (of 24)
CityVancouver, Can
Period6/22/976/26/97

ASJC Scopus subject areas

  • Engineering(all)

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    Zhou, Y., Wexler, A. S., & Wang, L. P. (1997). On the collision rate of small particles in isotropic turbulence Part 2. Finite inertia case. In American Society of Mechanical Engineers, Fluids Engineering Division (Publication) FED (Vol. 17). ASME.